Sixty-five years ago a small group of maverick thinkers gathered in a converted Buddhist museum on the outskirts of Cambridge, convinced that language held the key to unlocking artificial intelligence. Their leader was the extraordinary and eccentric Margaret Masterman – religious devotee, linguist, logician, philosopher, self-made computer scientist, and forgotten prophet of AI.

With the discovery of an archive that had remained unopened for nearly forty years, Peter de Bolla has pieced together the remarkable story of Masterman's creation and direction of the Cambridge Language Research Unit (CLRU). Working on the fringes of the university, dismissed as an amateur and constrained by structural sexism, Margaret Masterman, who took dictation from Wittgenstein, led the CLRU to the discovery of AI as they worked at an extraordinary pace to crack the problem of machine translation. Taking Turing's theoretical proposal of an 'electronic brain' and running furiously with it, she and her colleagues built the first machine that could think - a machine capable of engaging with human minds, and even, in Masterman's prophesised future, of doing philosophy alongside them.

Her audacious claim that a machine could generate meaning, not merely manipulate symbols made – and still makes – her both a prophetic voice and a heretic. Blending biography, intellectual history, the drama of scientific revolution, and the exhilarating discovery of the most powerful technology of the twenty-first century, AI, this book reveals how Masterman and her collaborators – from philosophers, linguists and botanists to quantum theorists – came to formulate a theory of language and mind that we are only now beginning to see in action in the large language models that shape our world today.